• CN 62-1175/P
• ISSN 1006-7639

Journal of Arid Meteorology ›› 2021, Vol. 39 ›› Issue (3): 357-365.

### Characteristics of Spatial Temporal Variation of Dryness and Wetness from 1978 to 2017 in Southwestern China

ZHOU Xiyin1,2,3, LI Xiehui1#br#

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1. 1. Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences,
Chengdu University of Information Technology, Chengdu 610225, China;
2. Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions,
Chinese Academy of Sciences, Northwest Institute of EcoEnvironment and Resources,
Chinese Academy of Sciences, Lanzhou 730000, China;
3. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
• Online:2021-06-30 Published:2021-07-16

### 1978—2017年西南地区干湿时空变化特征

1. 1.成都信息工程大学大气科学学院，高原大气与环境四川省重点实验室，四川成都610225；
2.中国科学院西北生态环境资源研究院，中国科学院寒旱区陆面过程与气候变化重点实验室，
甘肃兰州730000；3.中国科学院大学资源与环境学院，北京100049
• 通讯作者: 李谢辉（1977— ），女，新疆石河子人，博士，副教授，主要从事气象灾害与极端气候变化研究. Email: lixiehui325328@163.com。

Abstract:  Based on SPEI of 91 meteorological stations with time scales of 1, 3, 6 and 12 months from 1978 to 2017 in southwestern China, the spatialtemporal variation characteristics of dryness and wetness were analyzed by means of ESMD, MK mutation test and spatial interpolation methods. The results are as follows: (1) In the past 40 years, in the southwestern region it presented a trend of aridification. The mode components decomposed by ESMD had interannual oscillation (2 a) and interdecadal oscillation (10 a) feature and the trend components showed a fluctuating decline. There was no recovery after 2010 and drought degree was gradually deepening. (2) The ESMD and MK mutation test were combined to obtain the dryness and wetness mutation time and it was in the early 2000s. (3) The drought intensity was negatively correlated with the wetness intensity, it was mainly drought in most regions. Extreme drought occurred in the northwest Sichuan and the central and eastern Guizhou, while the wet intensity in southern Sichuan was higher. (4) In terms of spatial distribution of seasonal average dryness and wetness intensity, extreme dryness and wetness appeared in spring, most of the areas were humid, and extreme drought occurred in some parts in summer. Drought occurred with different degrees in autumn and winter, and local humidity appeared in some areas.